Improvement in hot-air engines



cf. P. LEA-VUT;

HlotU-Air-Engines.

N0. 133649. Patented Dec. 3,1872.

Il -f-ess] bwl Hff i i i yx l u N 5,4 -r A' l 1 i 1 i iE H HIE @S Wlfnf'myesf I Inventar Mwp To all whom't may concern:

PATENT OFFICE. y

' CHARLES?.- LEAVITT, OF NEW YORK, N.` Y.

IMPROVEMENTlN lHOT-AIR ENGINES.

VSpecification forming part of Letters Patent-No. 133,649, dated Decen1bcr.3,l872.

Be it known that I, cnrs. nmavrrr, of

New York, in the county and State of New York, have invented 4a new and useful -Improvernent in Hot-Air Engines; and I do hereby declare that the following is a full and exact description thereof, reference being had to the accompanying drawing and-to the letters of reference marked thereon forming a part of this specification. A, i Y

My invention relates to 'that class of hot-air engines where the product of the combustion *of the fuel enters the cylinder of the en gine.` The principal features of my engine are,

first, the direct passage of the product of the 'combustion of the Vfuel into the cylinder without the int'erposition of a valve, which would always be liable to derangement on account 'of the heat to which it would be subjected; second, constructing the pump oi' anequal capacity with the cylinder and discharging a portion of its contents under the exhaust-valve to keep it vcool and free from dust and ashes; this feature also gives the `engine less negative force than'any other 4form of air-engine using a pump; third, means for supplyin g the -flre regularly with fuel without stopping the engine or in any way interfering with its perfect action. y Y

To enable others skilled in the art to make and; use my invention Iv will now describe its construction and mode of operation.

In the drawing, Figure 1 is aside elevation of the engine,and Fig. 2 is a vertical section through the center.

Both views' are'drawn in the same plane,

and similar letters refer to similar parts.

y A isthema-in.. cylinder,`which is more than twice the'stroke of the crank in length, and is considerably larger in diameter at the lower partthan it is at the upper part. This is to allow the cylinder to be lined in its lower part with the non-conducting material a, to resist the passage of heat. -When this lining has been introduced the cylinder becomes of a uniform bore throughout. The lining a also .extends over the lower head and the surface of the fire-box O, as shown. Fitted within the cylinder A, so as to be as large as possible without touching it, is the piston or plunger C. This is, indepth, greater than the stroke of the piston, and is mainly composed of a non-conducting material. The upper end is made of metal, neatly fitting the cylinder,

and is packed with the ring of cupped leather U. The plunger has a small prolongation to descend into the {ire-box O, and thus diminish the amount of clearance. The plunger is hollow, to allow the lower end of the connectingrod b to be jointed as low as possible, and thus diminish the vertical height of the engine. This rod connects in the usual manner with the crank S at its upper end. By this arrangement the piston-packing C alwaysftravels on the upper end of the cylinder, the metal ot' which is cold. In the hot portion of the cylinder there is no'friction, since the plunger G does not touch the cylinder. E is the barrel ofthe pump, E the piston, and F the crank that drivesit. This crank is at right angles (more or less, according to the amount of heat4 given to the air) to the crank S, and follows it. The pump induction-valve is marked t', and the eduction-valve e. The valve d is the exhaust-valve, and is so moved by the rolling cam cl that it is open when the piston Gis descending and closed when it is ascending. M is an opening through which the air, in leaving the cylinder A, passes to the passage t and Y the eXhaust-valved; and mis a continuation of the passage t leading under the grate p of the `{ire-box O. Whether the air, on entering or leaving the cylinder, passes through the passage M or the passage w depends on the position of the valve a. This valve, being pivoted on one side, can be made to close either passage. It has a motion coincident in time with the valve d, being moved by the same cam, (see Fig. 1,) and on the downstroke of the engine always closes the passage w, as shown in Fig. 2. In Fig. 1 r is the rod that gives motion to the valve by acting on the arm xed to its axis, where it extends beyond the base, as shown. The upper end of this rod connects with the link l, which receives its motion from the cam-rod of the cam inder to pass through the re yet, if secured jf@ at any point nearer the axis of l, will only partially close that passage. This valve `-thus serves to regulate the amount of air that must pass through the re to enter the cylinder. In order to supply the fire with fuel the horizontal tube R is arranged in connection with the fire-box O. This tube is tted with the piston f, tapped to fit the screw f', by which it is moved. The pipe R is fitted with a detachable head, through which the screw passes to receive the wheel W, by which it is turned. G is an opening, closed by a proper valve or hand-plate, by which access is given to the lire-box above the grate for kindling the fire;

and g is a similar opening to admit of cleaning below the grate. The handle j is for the purpose of shaking the grate, it being pivoted in the usual manner for that purpose. It is the ily-wheel, and h the pipe that conveys away the exhaust air.

In using this engine the piston f in the pipe R is screwed back against the head and the space in front of the piston filled with coal. As much water is then introduced into the pipe R as it will contain without overflowing into the {ire-box, the water being introduced to prevent the coal taking re and to reduce the clearance. The pipe is of suicient capacity to hold enough coal to run the engine twelve hours, or more, if desired. It will now be clearly seen that by turning the screw in the proper direction the piston f will be forced with great power against the coal, thereby forcing it up the bent portion of the tube and out ofthe water, when it falls onto the regrate, as shown in the ligure. The screw can be turned at a given rate by the engine itself, whenthe firing will become automatic. At

.. the moment of revolution, shown in the drawing, the piston G is falling and the heated air is being forced out from beneath trthrough the passage M and the valve d. The pump-piston E', immediately following, also forces cold air into the -passage t, which mingles 4with the air from the cylinder A and escapes with it. When the piston C is at the bottom of its stroke the current of hot air from the cylinder A ceases, and, as at that time the pump-piston is only half down and moving with its greatest velocity, the last air passing through the valve d is pure and cold. At this instant vthe valve closes, and, at the same time, the valve n is lifted, opening the passage a: and closing or partially closing the passagevM.

The closing of the valve d prevents the escape of any more air from the engine, and the halfcyliuder of air thus confined in the pump is made to yield before the advance of the piston Ef, part-ly by condensation and partly by escaping through the cducti'on-valve and the passages, shown through there, to the cylinder A, the piston of which at once begins t-o rise. When .the piston E is at the bottom of its stroke the piston C is half Way upon its return stroke. The air which was in the pump on the closing of the valve d has been transferred to the cylinder A without change of final volume. The air being heated, its pressure is, say, doubled. The air then expands to the endv of the stroke within the cylinder A, when its pressure falls to that of the atmosphere, the pump, meantime, making half its .up stroke,'drawing air through the induetionvalve i, the eduction-valve being held closed by the pressure within the cylinder A. The valve d then opens as before, the valve n closes over the passage au, and, on the descent of the piston G, the air escapes, as already described, the air from the cyliuderfbeing mixed with, and then superseded by, the air from the pump during and after the last half-down stroke of the piston C.

Although I have described the crank F as at right angles to thev crank S, and have supposed the pressure of air to be duplicated, it was merely for convenience of description. It is not likely that such a result will be often reached; and, as it is not desirable that the terminal pressure in the cylinder A should fall below the atmosphere, these cranks will most frequently have a greater inside angle than ninety degrees and less than one hundred and thirty degrees.

This engine admits of the introduction of the regcnerator between the passage M and the valve d.

What I claim as my invention, and desire to secure by Letters Patent, is v 1. The cylinder A and the pump E, of equal size, combined, arranged, and operated substantially as described.

2. The arrangement, in the air-engine hercin described, of the tube R, fitted with the pisv ton f, submerged in water, and the screw j", constructed substantially as and for the purpose specified.

3. The valve n, in combination with the passages M vand arranged substantially as described, and for the purpose as set forth.

4. The valve d, in combination with the pump E and the cylinder A, arranged substantially as described, and for the purpose as set forth.

CHARLES P. LEAVITT.

Witnesses l W. F. SrEARNs, Cru-s. HALLETT CLARK. 

